Peak Attenuation (active tone control!)

Asmith · Post by **Asmith** » 13 Jul 2017, 19:32

Hi, new to the forum. Starting a thread on a tone circuit I've designed for a guitar I just acquired along with cheap SS amp and some other stuff. The guitar is a 2004 CII Squier Affinity Stratocaster and I'm going to mod the snot out of its controls. Previously I've tried a varitone type circuit in another guitar and didn't care for the rotary switch control, I kept getting cap popping noises when switching. I still wanted a circuit that would alter the tone by changing the tone capacitor value rather than the resistance in series with that capacitor. I found a capacitance multiplier circuit and built on that using Circuit Lab to perform simulations, a great software I couldn't recommend it more if you do this kind of thing on a regular basis.

Here's the schematic I drew up of the circuit,

stratocaster-ultra by ashleyjsmith1996, on Flickr

Followed by some frequency response sweeps

Peak shift sweep,

As you can see the resonant peak can be shifted, the range can be adjusted by altering the resistors in the Variable Capacitor section of the circuit. The Peak VR should be a log Potentiometer but I think finding the part may be tricky.

Peak Sweep by ashleyjsmith1996, on Flickr

Bass cut sweep,

Pretty much a standard bass cut circuit like you would find on a reverend or a G&L, different component values based on my previous experience again would ideally need a reverse log pot.

Bass Sweep by ashleyjsmith1996, on Flickr

Volume sweep,

Just wanted to show that the buffer's doing its job.

Volume Sweep by ashleyjsmith1996, on Flickr

I've played around combining pot positions to make sure that everything behaves well and it does so that's good.

I just need to get this thing wired up and then make a few adjustments to some component values if something doesn't sound ideal.

Let me know what you think and if anyone knows where I can get a half decent 500k reverse log pot let me know otherwise I'm wiring them backwards also the OP amp is powered using 2 9v batteries in series with a centre tap to ground.